Integrated laser/phototransistor optoelectronic switching device by organometallic vapour phase epitaxy

Computer-controlled organometallic vapour phase epitaxy has been used to optimise AlGaAs/GaAs quantum well lasers and bipolar phototransistors separately. Here the two structures are combined In a single growth to realise a high-performance two-terminal optoelectronic switch. DC I/V characteristics are typical of an npnp structure; however, the feedback mechanism is optical rather than electronic. Threshold switching voltage is determined by the optical input in the range 1.3¿23 V and sensitivity is 2.5 V/¿W. Output is both optical (laser) and electrical current. Gain is provided by the phototransistor and optical feedback and exceeds 104. Switching speed is determined to be less than 1 ns.